Organic light emitting diodes (OLEDs) utilize thin film materials which emit light when excited by electric current. This makes OLEDs a popular alternative technology for flat panel displays.
OLEDs may be fabricated using shadow mask deposition technology. In shadow mask deposition, organic-based films, which form red, green, and blue (R, G, B) OLED pixels, may be deposited in a vacuum over the parallel arrays of transparent anode strips using a shadow mask 20 as shown in FIG. 1. The shadow mask 20 has a plurality of openings 22 through which the films of the OLEDs are evaporated over the arrays of transparent anodes disposed on a transparent substrate 10.
In order to lower fabrication costs, the transparent substrates on which the OLEDs are fabricated are increasing in size. This allows a plurality of display panels to be fabricated from a single substrate. In order to process these larger substrates, the shadow masks have also been enlarged. However, these larger shadow masks tend to sag toward their centers, thus loosing dimensional accuracy.
Accordingly, a shadow mask is needed which does not sag toward the center thereof.